int vfs68_seek_to(vfs68_t *vfs, int pos) { int cur = vfs68_tell(vfs); return isseek(vfs, cur, pos-cur); }
int istream_seek_to(istream_t *istream, int pos) { int cur = istream_tell(istream); return isseek(istream, cur, pos-cur); }
int vfs68_seek(vfs68_t *vfs, int offset) { return isseek(vfs, vfs68_tell(vfs), offset); }
int istream_seek(istream_t *istream, int offset) { return isseek(istream, istream_tell(istream), offset); }